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Editorial |
Division of Surgical Oncology, Northwestern Medical Faculty Foundation, 201 E. Huron, 10-105, Chicago, Illinois 60611
Correspondence: Address correspondence and reprint requests to: Mark Talamonti, MD; E-mail: mtalamonti{at}nmff.org.
In this issue of Annals of Surgical Oncology, Varadhachary et al.1 from the M. D. Anderson Cancer Center (MDACC) describe their institutional experience with a subset of patients previously considered to have locally advanced, unresectable cancers and now perhaps better classified as having borderline-resectable tumors. The article is important because it comes from the surgical group that has been preeminent in defining the radiographical criteria that correlate with surgical resectability. It is significant for its further refinement of these criteria and provocative in its proposal to classify patients with more significant mesenteric vascular involvement as potentially resectable after neoadjuvant therapy. The article has several major points relevant to surgical oncologists caring for patients with pancreatic cancer.
Previous reports from MDACC have defined the critical aspects that need to be evaluated in a thorough radiographical assessment of a potentially resectable pancreatic cancer. These are the presence or absence of peritoneal or hepatic metastases; the patency of the superior mesenteric vein and portal vein and the relationship of these vessels and their tributaries to the tumor; the relationship of the tumor to the superior mesenteric artery, celiac axis, hepatic artery, and gastroduodenal artery; and the presence of any aberrant vascular anatomy.2 Standard criteria for resection include the absence of distant metastases, limited mesenteric venous involvement with patency of the portal vein and superior mesenteric vein, and no evidence of major arterial encasement.
The authors now propose a relatively new category defined as borderline-resectable pancreatic cancer. Criteria for this group of patients include encasement of a short segment of the hepatic artery without evidence of tumor extension to the celiac axis; tumor abutment of the superior mesenteric artery involving <180° of the artery circumference; and short-segment occlusion of the superior mesenteric vein/portal vein confluence beneath the neck of the pancreas. Whether these patients would benefit from an initial approach with chemoradiation, repeat staging studies, and subsequent exploration is the subject of this article.1 The critical need for a complete margin-negative resection (R0) is appropriately emphasized by the authors. Series examining survival data based on margin status demonstrate similar survival rates for margin-positive resections compared with non-operative local-regional therapies in patients with locally advanced disease. Data from this same surgical group have demonstrated the safety and utility of venous resection in highly selected patients with localized head-of-pancreas cancers in which a margin-negative resection could be accomplished only by the addition of venous resection. Perioperative morbidity was low, and ultimate survival rates were comparable to those for patients undergoing R0 resection without vein resection.3 The median survival in both groups was approximately 2 years. Computed tomography accurately predicted the need for vein resection and reconstruction in most patients. This is critical because preoperative awareness of vascular involvement will facilitate intraoperative technical approaches and minimize the potential danger of adding a vascular procedure to the already formidable task at hand.
The success of major venous resections secondary to local tumor extension has led this group to consider even more aggressive resections after neoadjuvant therapy for lesions now categorized as borderline resectable. The stated objectives of this article are to present the institutional criteria used for radiographical staging and identification of patients with borderline disease and to present a rationale for the use of combined-modality preoperative therapy. Certainly, the first objective is well met and presented concisely and clearly. The stated basis for preoperative therapy for borderline-resectable disease is essentially the same rationale used to justify preoperative therapy in patients with any potentially resectable tumor. True justification for the role of preoperative therapy in patients with borderline-resectable pancreatic cancer will eventually need to include outcome data on borderline patients treated at MDACC who either did or did not ultimately undergo surgery. Four representative cases are described, and these serve quite clearly to address the pertinent radiographical and clinical issues. However, they only whet the reader’s appetite for more data on all patients seen at the institution, including borderline cases who underwent preoperative therapy. Before this algorithm of treatment can be accepted as a standard of care, institutional data on their experience with patients with borderline tumors treated with preoperative therapy and the intent of ultimately undergoing resection (resection rates, margin-negative rates, complications, median survival, and so on) will need to be presented, as has been done in the past for limited venous resections. Similarly, the authors note that the radiographical tumor response and tumor marker reduction were predictors of successful resection and survival. Although this was true for the four cases presented, it will be important to know how often such responses can be expected and what is the best way for measuring treatment effects.
Finally, the authors offer a clear and very short discussion of options for preoperative combined-modality therapy. Their institution has a great deal of experience with 5-fluorouracil–based chemoradiation and also more recently with gemcitabine-based chemoradiation. The optimal combination and regimen of preoperative chemoradiation remains an area of active investigation. Recent studies suggest greater response rates with no marked increase in complications with gemcitabine-based chemoradiation.4 The use of a highly effective treatment regimen will be critical if one end point used to determine resectability is the extent of tumor response. The notion of extended or radical pancreaticoduodenectomy is not novel, and, unfortunately, previous results suggest that it is not effective in patients with locally advanced pancreatic cancers.5,6 The challenge remains 2-fold: being able to add the technical complexity of venous and/or arterial resection and reconstruction to an already difficult operation and being able to show that it has a significant and favorable effect on patients’ quality of life and overall survival. As concluded by the authors, a prudent approach to these patients may be a course of effective preoperative chemoradiation (as yet to be determined) followed by repeat staging studies with a highly selective and judicious use of venous and limited arterial resection and reconstruction. Time and more experience will determine whether this is indeed an effective strategy. Needless to say, this should be done by surgical oncologists who have a specialized focus on pancreatic cancer and surgery—preferably under the auspices of a clinical research trial.
Received for publication February 15, 2006. Accepted for publication February 21, 2006.
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